The crystallization of thin Sb2Te films with vacuum annealing and an electron beam published by Ural Federal University eISSN 2411-1414 chimicatechnoacta.ru ARTICLE 2023, vol. 10(1), No. 202310111 DOI: 10.15826/chimtech.2023.10.1.11 1 of 7 The crystallization of thin Sb2Te films with vacuum annealing and an electron beam Anton A. Yushkov *, Vladimir Yu. Kolosov Institute of Natural Sciences and Mathematics, Ural Federal University, Ekaterinburg 620026, Russia * Corresponding author: Yushkov.anton@urfu.ru This paper belongs to a Regular Issue. Abstract Thin Sb2Te films with a thickness gradient were studied via transmission electron microscopy. The processes of forced crystallization were examined with thermal annealing and an electron beam. The crystallization’s general tendencies, including competitive nucleation and growth crystallization, were revealed. As the thickness of the sample increases, the size of the crys- tals growing in the film enlarges. As the temperature increases, the number of crystals in the film grows. Crystallization under the action of an electron beam occurs mainly by nucleation mechanism. Keywords Sb2Te thin films phase-change materials transmission electron microscopy Received: 24.12.22 Revised: 17.02.23 Accepted: 21.02.23 Available online: 03.03.23 Key findings ● A thin amorphous Sb2Te film crystallizes in a phase isomorphic to antimony during vacuum annealing. ● During annealing, the processes of nucleation and growth crystallization proceed competitively in the film. As the temperature rises, nucleation predominates. ● The possibility of controlled creation of crystalline regions in an amorphous Sb2Te film by exposure to a focused electron beam is shown. © 2022, the Authors. This article is published in open access under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). 1. Introduction Sb–Te systems, including Sb2Te and compositions based on it, are considered as perspective thermoelectric materials [1–4]. Characteristic of the amorphous state crystal phase transition in these materials has a critical impact on their properties [5]. The non-linear optical properties of these materials open up prospects for their application in optoe- lectronics [6–8]. These compositions are also advanced ma- terials for manufacturing non-volatile memory based on the phase transition effect (PCM) [9–15]. The development of multi-level memory cells that are competitive with modern flash memory devices is underway [16, 17]. Unlike other phase-change materials, Sb–Te systems are characterized by a high crystallization rate and thermal stability [13]. The properties of antimony telluride as a topological insulator [18, 19] and a high-temperature superconductor [20] have also been studied. In order to increase the stability and performance of devices, various dopants are used [12, 13, 15, 21–24]. In particular, the use of carbon carbide leads to an increase in the crystallization temperature and an increase in the number of PCM memory rewriting cycles [24]. The addi- tion of scandium and yttrium to antimony telluride leads to a reduction in thermal conductivity and an increase in the energy efficiency of PCM devices [23]. The features of the phase transition in materials based on Sb–Te as a func- tion of temperature [16, 25] and composition changes [22] are investigated. In the context of these applications, it is of interest to study the processes of crystallization in amorphous Sb2Te films in the context of temperature and impact of an electron beam. Studying the effect of temperature and sample thick- ness on the crystallization process will allow us to evalu- ate the thermal and mechanical resistance of finished de- vices. Also, indirectly, one can judge their electrical prop- erties. The proven method of exposure to a beam of a transmission electron microscope (TEM) is applicable both to further experiments and to the development of in- dustrial methods. http://chimicatechnoacta.ru/ https://doi.org/10.15826/chimtech.2023.10.1.11 mailto:Yushkov.anton@urfu.ru http://creativecommons.org/licenses/by/4.0/ https://crossmark.crossref.org/dialog/?doi=https://doi.org/10.15826/chimtech.2023.10.1.11&domain=pdf&date_stamp=2023-03-03 Chimica Techno Acta 2023, vol. 10(1), No. 202310111 ARTICLE 2 of 7 DOI: 10.15826/chimtech.2023.10.1.11 2. Materials and experimental methods The samples were synthesized by the group led by Professor M. Wüttig at RWTH Aachen University (Germany). The sam- ples were gradient films (in the order of hundreds of mi- crons) of Sb2Te deposited on carbon-coated grids via mag- netron sputtering. The thickness gradient in the samples was created using a shading plate. Shortly after synthesis, the samples were subjected to vacuum annealing at various temperatures and times. According to the energy-dispersive X-ray spectroscopy, the specimens retain the nominal chemical composition throughout the area. In this work, the following goals were set. Firstly, the study seeks to investigate patterns of crystallization in thin films along the thickness gradient, depending on the type of exposure, time and annealing temperature. Secondly, the study will determine the features of the formed crystal structures: the phase composition and the main crystallo- graphic orientations. Sb2Te samples were studied via transmission electron microscopy on JEOL JEM-2100. According to the analysis of zone-axial patterns (ZAP) in the samples and the interpre- tation of the corresponding electron diffraction patterns (examples are shown in Figure 1), crystallographic orienta- tions of the antimony phase predominate in the crystallized films (ASTM 05-0562, trigonal syngony, space group R3̅m). According to the measurements of the secondary diffraction maxima in the dark field mode [26], the thickness of the crystallized film varies along the gradient from about 15– 20 nm to 40–50 nm over several tens of micrometers. 3. Results and Discussion The Sb2Te 145C-60s sample was annealed at 145 °C for 60 seconds. In the thinnest area of the thickness gradient, the film is predominantly amorphous (Figure 2a). Along the thickness gradient, the substance crystallizes into separate island-crystallization centers, often with a hexagonal facet- ing motif, ranging in size from 0.4 µm at the beginning of the thickness gradient to 2 µm in the thickest region. The initial amorphous film’s strong relief, which is characteristic of magnetron sputtering, is ignored by crystallization. As we move along the thickness gradient, the size and number of such islands increases. They fill an increasing area of the film and merge, forming a continuous crystalline field (Fig- ure 2c, d). The TEM images do not show a connection be- tween crystallization centers and any defects or features of the film relief. In the film’s thickest region, the crystallites measure 1–2.5 µm. The Sb2Te 145С-48s sample is similar to the 145С-60s in terms of the morphology, sizes and observed zone-axial pat- terns of the formed crystallites; therefore, a detailed study was not carried out. The sizes of the crystallites range from 0.2 µm at the beginning of the thickness gradient to 2.8 µm in the thickest region. A small change in the annealing time did not significantly affect the formed crystal structure. Figure 1 Samples Sb2Te and (145C-48s (a) and 145C-60s (b, c, d)) ZAP (left), the corresponding indexed electron diffraction patterns of the selected area (right). a – ZAP with zone axis orientation [͞111] (a); ZAP with orientation [001] (b); ZAP [̅225]; d - ZAP [2 ̅2 1] (c). The Sb2Te 120C-90m sample was annealed at 120 °C for 1.5 hours. The pattern of crystallization before the formation of a continuous film was similar to Sb2Te 145C-48s and Sb2Te 145C-60s – hexagonal crystalline islands of increasing size and density along the thickness gradient (Figure 3a–c). In the thinnest area, the crystal sizes ranged from 100 to 700 nm. In the thickest continuous film, the crystallites measured 1– 3 μm. In the Sb2Te 120С-90m sample, the largest crystals were observed in the thickest region. The Sb2Te 200C-48s sample was annealed at 200 °C for 48 seconds. In this sample, the crystallization processes along the thickness gradient differ from those in the Sb2Te 145C-48s, Sb2Te 145C-60s and Sb2Te 145C-90m samples. Near the phase boundary, the film crystallizes into a homo- geneous fine-grained field (Figure 4a, b), with crystal sizes ~10–50 nm. As the thickness of the film increases, the sizes of the crystallites grow, and there are no areas of the amor- phous phase between them (Figure 4c, d). This indicates that nucleation in the film increases as annealing temperature in- creases. This process is enhanced as the sample thickness de- creases. The crystallites in the thickest region measure 0.3– 1.8 μm, smaller than in the previously considered samples. https://doi.org/10.15826/chimtech.2023.10.1.11 Chimica Techno Acta 2023, vol. 10(1), No. 202310111 ARTICLE 3 of 7 DOI: 10.15826/chimtech.2023.10.1.11 Figure 2 TEM images of the 145С-60s sample at the beginning of the thickness gradient, with a noticeable relief of the initial amorphous film and small crystallites in the amorphous matrix (a, b); image taken from the middle of the gradient, crystalline areas are adjacent to amorphous ones (c); image of a completely crystallized area in the thickest area. Figure 1b, d provides the measurements of some crys- tallites (d). Figure 3 TEM images of the 120С-90m sample at the beginning of the thickness gradient (successively upwards), with individual small/medium crystals in an amorphous matrix (a, b); image of the sample in the area from the middle of the gradient (c); image of the sample in the thickest region. Figure 3b, d show the measurements of the linear dimensions of some crystallites (d). https://doi.org/10.15826/chimtech.2023.10.1.11 Chimica Techno Acta 2023, vol. 10(1), No. 202310111 ARTICLE 4 of 7 DOI: 10.15826/chimtech.2023.10.1.11 Figure 4 Image of the thinnest area of the 200C-48s sample, individual small crystals are distinguishable (a); images from the gradient’s middle (in the direction of increasing thickness) (b, c); image from the thickest region (crystallites reach their maximum size) (d). In the samples 120С-90m, 145C-60s and 145C-48s, the growth of individual crystals with a hexagonal faceting mo- tif was observed. The general trend of crystallization is an increase in crystal size as the film thickness increases. Changing the annealing conditions affected the crystallized films’ morphology. With an increase in annealing time, an increase in the linear dimensions of the crystallites was ob- served: the largest crystals are observed for the 120C-90m sample annealed for 1.5 hours. An increase in annealing temperature led to the growth of smaller crystals. In the sample annealed at 200 °C, a finely crystalline film was formed in the thinnest region instead of individual crystal nuclei. In the thickest region, the crystallites in this sample were the smallest among all the samples. This indicates an increase in nucleation as annealing temperature increases and film thickness decreases. The authors of [27] indicate an increase in nucleation (the appearance of many crystal- lization centers in an amorphous matrix) in chalcogenide films based on Sb2Te and a decrease in thickness (in exper- iments with simultaneous heating and exposure to a TEM beam). They call this effect paradoxical: if nucleation crys- tallization occurs on the sample film’s surface, then it should not depend on the thickness. If nucleation develops in the bulk of the sample, then a larger number of crystalli- zation centers should appear in a thicker film. Higher annealing temperatures were characterized by the growth of smaller crystals throughout the thickness gradient, especially in the thinnest regions. This points to the presence of a nucleation mechanism of crystallization. Longer annealing times and lower temperatures were char- acterized by the growth of larger crystals (growth crystallization). This can be explained by the nucleation of a smaller number of crystallization centers at a lower tem- perature. A time factor of tens of minutes obviously has lit- tle or no effect on crystallization. The morphology of the samples with an annealing time of tens of seconds or tens of minutes differs insignificantly. The crystals probably formed within a few seconds. The general trend for the en- tire group of samples is an increase in the size of the formed crystallites and their density on the film as the thickness increased. Fully crystallized by thermal annealing, the film was paved with crystallites of various sizes and arbitrary shapes. No ordering or separate isolated crystallization centers were observed in the samples. This can be explained by the mutual blocking of the growth of neighboring crys- tals that arise almost simultaneously from numerous crys- tallization centers. The sample 48s-200C was also distin- guished by the fact that, contrary to the general trend, it had the largest number of crystallization centers on the thinnest part. In the temperature range from 145 °C to 200 °C, there is probably a value at which the effect of tem- perature begins to prevail over the effect of film thickness on the crystallization of Sb2Te samples. All the samples were characterized by the same predom- inant crystallographic orientations, which was determined by electron diffraction data and observed ZAP – [1̅11], [001], [2̅25], [22̅1], [122]. According to the interpretation of the electron diffraction patterns, the substance crystallized in a phase isomorphic to that of antimony. This phenomenon is characteristic of chalcogenide compounds. In the case of antimony-based materials, this is usually the antimony phase. Here, this phase’s lower crystallization temperature https://doi.org/10.15826/chimtech.2023.10.1.11 Chimica Techno Acta 2023, vol. 10(1), No. 202310111 ARTICLE 5 of 7 DOI: 10.15826/chimtech.2023.10.1.11 may have an effect [28]. The percentage of elements can also play a role. Such is the case for Bi–Sb films with a pre- dominance of bismuth, which crystallize in the bismuth phase [29]. This may mean that there is a lower Sb–Sb bind- ing energy (similar to In–Sb [30]), although other factors may be responsible. An amorphous Sb2Te film was exposed to a focused elec- tron beam in a microscope column (Figure 5). The exposure was carried out for 1 min at an accelerating voltage of 200 kV and a beam of maximum intensity (without considering the diaphragms in the TEM column). The current density on the sample was about 10 MA/m2. As a result, in the initially amorphous film (Figure 5a), a polycrystalline region with a diameter of about 1 μm was formed (Figure 5b, c). An in- crease in the size of crystallites in the radial direction from the center was observed. Examination of the obtained ring electron diffraction pattern (Figure 6, Table 1) revealed crys- tallization in the antimony phase. A number of weak reflec- tions in the electron diffraction pattern (Table 1, nos. 10–13) were not correlated with antimony, tellurium or antimony telluride phases. They correspond to small interplanar dis- tances, no data on which are available for these substances from the databases of ASTM X-ray diffraction analysis. 4. Limitations For further studies, it is necessary to prepare a series of sam- ples with a fixed annealing temperature step. A more accu- rate assessment of the thermal effect on the sample of the TEM electron beam will also be useful. The currently availa- ble equipment also allows simultaneous exposure to an elec- tron beam and heating of the sample substrate in situ. Figure 6 Electron diffraction pattern of the area exposed to an elec- tron beam in the Sb2Te sample. White arcs with three-digit indices indicate ring reflections associated with the antimony phase; the arcs numbered 10–13 denote unidentified reflections. See Table 1 for the measurement and indication results. 5. Conclusions Due to annealing, the samples crystallized from the amor- phous state. In gradient Sb2Te samples subjected to vac- uum annealing, crystallization is observed to depend both on the film thickness and temperature. As the thickness of the sample increases, the size of the crystals growing in the film enlarges. As the temperature increases, the num- ber of crystals in the film grows. Also, with increasing temperature, the thickness at which crystallization is pos- sible decreases. During thermal crystallization, the pro- cesses of nucleation and crystal growth proceed competi- tively. No spontaneous crystallization was observed in the graded Sb2Te samples. Figure 5 TEM of a section of an amorphous film before exposure to an electron beam (a); TEM of the area after exposure to a focused electron beam (b); crystal structure grown in an amorphous matrix under the action of a beam (c); electron diffraction pattern from the structure in Figure 5c (d). (a) https://doi.org/10.15826/chimtech.2023.10.1.11 Chimica Techno Acta 2023, vol. 10(1), No. 202310111 ARTICLE 6 of 7 DOI: 10.15826/chimtech.2023.10.1.11 Table 1 Identification of antimony phase reflections on the ring electron diffraction pattern from a Sb2Te sample after exposure to an electron beam (Figure 6). No. of ring D, 1/nm dmeasured, Å Observed intensity, % dtheor, Å Intensity theor., % hkl 1 9.43 2.12 100 2.15 37 110 2 11.3 1.77 5 1.77 19 202 3 14.92 1.34 5 1.37 16 122 4 16.45 1.22 40 1.24 6 300 5 18.9 1.06 30 1.08 4 220 6 19.87 1.01 10 1.02 7 4–12 7 22.07 0.91 10 0.92 3 042 8 24.01 0.83 10 0.82 9 –254 9 24.95 0.8 30 0.8 4 235 10 28.12 0.71 5 11 28.71 0.7 5 12 30.5 0.66 5 13 33.82 0.59 5 Crystallization occurred during thermal annealing or exposure to a TEM beam. All the samples crystallized in a phase isomorphic to that of antimony. The character of crystallization of a magnetron-sput- tered Sb2Te film via a maximum intensity beam differs sig- nificantly from that in thermal crystallization. Crystalliza- tion under the action of an electron beam is characterized by the formation of polycrystalline regions according to the nucleation mechanism. In contrast to single crystals, a polycrystalline region is formed corresponding to the area of the beam impact. In the center of the region with a diameter of about 300 nm, where the highest intensity of the TEM beam was achieved, crystallites up to tens of nanometers in size are observed. This points to the nucleation mechanism of crystallization, i.e., the simultaneous nucleation of many neighboring crys- tallization centers. Outside the central region, much larger crystallites are visible, hundreds of nanometers in size, elongated in the radial direction from the center of the crys- tallization region. This points to the growth crystallization mechanism, i.e., the growth of the crystalline phase from individual crystallization centers located along the nuclea- tion region’s outer edge. ● Supplementary materials No supplementary materials are available. ● Funding This work was supported by Russian Foundation for Basic Research (grant no. 20-02-00906), www.rfbr.ru/rffi/eng. Financial support was provided by the Public Task of the Ministry of Science and Higher Education FEUZ 2023-0020. ● Acknowledgments The authors are grateful to Professor M. Wüttig for providing the samples for the study. ● Author contributions Conceptualization: V.Yu.K., A.A.Y. Data curation: A.A.Y. Formal Analysis: A.A.Y. Funding acquisition: V.Yu.K. Investigation: A.A.Y. Methodology: V.Yu.K., A.A.Y. Project administration: V.Yu.K. Supervision: V.Yu.K. Validation: V.Yu.K. Visualization: A.A.Y. Writing – original draft: A.A.Y. Writing – review & editing: A.A.Y. ● Conflict of interest The authors declare no conflict of interest. ● Additional information Author IDs: Anton A. Yushkov, Scopus ID 57193951559; Vladimir Yu. Kolosov, Scopus ID 7005960289. Website: Ural Federal University, https://urfu.ru/en. References 1. Xiao Z, Kisslinger K, Dimasi E, Kimbrough J. The fabrication of nanoscale Bi2Te3/Sb2Te3 multilayer thin film-based ther- moelectric power chips. Microelectron Eng. 2018;197:8–14. doi:10.1016/j.mee.2018.05.001 2. Champier D. Thermoelectric generators: A review of applica- tions. Energy Convers Manag. 2017;140:167–181. doi:10.1016/j.enconman.2017.02.070 3. Vieira EFM, Figueira J. Enhanced thermoelectric properties of Sb2Te3 and Bi2Te3 films for flexible thermal sensors. J Alloys Compd. 2019;774:1102–1116. doi:10.1016/j.jallcom.2018.09.324 4. Haidar SA, Gao Y. Deposition and fabrication of sputtered bismuth telluride and antimony telluride for microscale https://doi.org/10.15826/chimtech.2023.10.1.11 https://www.rfbr.ru/rffi/eng https://www.scopus.com/authid/detail.uri?authorId=57193951559 https://www.scopus.com/authid/detail.uri?authorId=7005960289 https://urfu.ru/en https://www.sciencedirect.com/science/article/abs/pii/S0167931718301989 https://www.sciencedirect.com/science/article/abs/pii/S0196890417301851 https://www.sciencedirect.com/science/article/abs/pii/S0925838818335825 Chimica Techno Acta 2023, vol. 10(1), No. 202310111 ARTICLE 7 of 7 DOI: 10.15826/chimtech.2023.10.1.11 thermoelectric energy harvesters. Thin Solid Films. 2021;717:138444(1–9). doi:10.1016/j.tsf.2020.138444 5. Voraud A, Seetawan T, Kumar M. Experimental and theoreti- cal study of thermoelectric properties of rhombohedral GeSb5Te10 thin films. MSEB. 2019;250:114439(1–5). doi:10.1016/j.mseb.2019.114439 6. Ding X, Yang X. Theoretical analysis and simulation of a tuna- ble mid-infrared filter based on Ge2Sb2Te5 (GST) metasurface. Superlattices Microstruct. 2019;132:106169(1–6). doi:10.1016/j.spmi.2019.106169 7. Cheng L, Yuan Y. Linear and nonlinear optical properties modulation of Sb2Te3/GeTe bilayer film as a promising satu- rable absorber. Results Phys. 2019;13:102282(1–7). doi:10.1016/j.rinp.2019.102282 8. Khusayfan, N. M. and Khanfar H. K. Characterization of CdS/Sb2Te3 micro/nano-interfaces. Optik. 2018;158:1154– 1159. doi:10.1016/j.ijleo.2018.01.010 9. Liu G, Wu L. The investigations of characteristics of Sb2Te as a base phase-change material. Solid State Electron. 2017;135:31–36. doi:10.1016/j.sse.2017.06.004 10. Liu B, Song Z, Feng S, Chen B. Characteristics of chalcogenide nonvolatile memory nano-cell-element based on Sb2Te3 mate- rial. Microelectron Eng. 2005;82(2):168–174. doi:10.1016/j.mee.2005.07.007 11. Ding K, Chen B, Rao F. Boosting crystallization speed in ul- trathin phase-change bridge memory device using Sb2Te3. Mater Sci Semicond Process. 2021;136:105999(1–6). doi:10.1016/j.mssp.2021.105999 12. Hu J, Lin C. Cr-doped Sb2Te materials promising for high per- formance phase-change random access memory. J Alloys Compd. 2022;908:164593. doi:10.1016/j.jallcom.2022.164593 13. Wang G, Shen X. Improved thermal stability of C-doped Sb2Te films by increasing degree of disorder for memory applica- tion. Thin Solid Films. 2016;615:345–350. doi:10.1016/j.tsf.2016.07.059 14. Yang C-H, Chiang K-C, Hsief T-E. Nonvolatile floating gate memory characteristics of Sb2Te–SiO2 nanocomposite thin films. Thin Solid Films. 2013;529:263–268. doi:10.1016/j.tsf.2012.07.135 15. Liu F, Wang G, Zhang Y, Li C. Improved multi-level storage performance by insulator-metal transition of In2S3-doped Ge2Sb2Te5 films. Ceram. 2019;45:24090–24095. doi:10.1016/j.ceramint.2019.08.116 16. Lotnyk A, Hilmi I, Behrens M, Rauschenbach B. Temperature dependent evolution of local structure in chalcogenide-based superlattices. Appl Surf Sci. 2021;536:147959(1–8). doi:10.1016/j.apsusc.2020.147959 17. Jiang K, Lu Y. GeTe/Sb4Te films: A candidate for multilevel phase change memory. MSEB. 2018;231:81–85. doi:10.1016/j.mseb.2018.10.002 18. Kampmeier J, Weyrich C. Selective area growth of Bi2Te3 and Sb2Te3 topological insulator thin films. J Cryst Growth. 2016;443:38–42. doi:10.1016/j.jcrysgro.2016.03.012 19. Bera S, Behera P. Weak antilocalization in Sb2Te3 nano-crys- talline topological insulator. Appl Surf Sci. 2019;496:143654(1–6). doi:10.1016/j.apsusc.2019.143654 20. Buga SG, Kulbachinskii VA. Superconductivity in bulk poly- crystalline metastable phases of Sb2Te3 and Bi2Te3 quenched after high-pressure–high-temperature treatment. Chem Phys Lett. 2015;631:97–102. doi:10.1016/j.cplett.2015.04.056 21. Choi M, Choi H, Ahn J, Kim YT. Material design for Ge2Sb2Te5 phase-change material with thermal stability and lattice dis- tortion. Scr Mater. 2019;170:16–19. doi:10.1016/j.scriptamat.2019.05.024 22. Nolot E, Sabbione C. Germanium, antimony, tellurium, their binary and ternary alloys and the impact of nitrogen: An X- ray photoelectron study. Appl Surf Sci. 2021;536:147703(1– 21). doi:10.1016/j.apsusc.2020.147703 23. Peng L, Li Z. Reduction in thermal conductivity of Sb2Te phase-change material by scandium/yttrium doping. J Alloys Compd. 2020;821:153499(1–7). doi:10.1016/j.jallcom.2019.153499 24. Meng Y, She Q. Uniform silicon carbide doped Sb2Te nano- material for high temperature and high speed PCM applica- tions. J Alloys Compd. 2016;664:591–594. doi:10.1016/j.jallcom.2016.01.036 25. Pandey SK, Manivannan A. Direct evidence for structural transformation and higher thermal stability of amorphous InSbTe phase change material. Scr Mater. 2021;192:73–77. doi:10.1016/j.scriptamat.2020.10.014 26. Delavignette P, Vook RW. Method for measuring the thick- ness of thin bent foils in transmission electron microscopy. Phys Stat Sol. 1963;3:648–653. doi:10.1002/pssb.19630030406 27. Kooi BJ, De Hosson ThM. On the crystallization of thin films composed of Sb3.6Te with Ge for rewritable data storage. J Appl Phys. 2004;95(9):4714–4721. doi:10.1063/1.1690112 28. Song SA, Zhang W, Jeong HS, Kim J-G, Kim Y-J. In situ dy- namic HR-TEM and EELS study on phase transitions of Ge2Sb2Te5 chalcogenides. Ultramicroscop. 2008;108. doi:10.1016/j.ultramic.2008.05.012 29. Ryu H, You Y, Paek MC, Kang K. Microscopic behavior of Sb in chalcogenide materials for crystallization process. Mater Sci Eng A. 2007;449:573–577. doi:10.1016/j.msea.2006.02.421 30. Kim YT, Kim ET, Kim CS, Lee JY. Phase transformation mech- anism of In–Sb–Te through the boundary reaction between InSb and InTe. Phys Stat Sol. 2011;5(3):98–100. doi:10.1002/pssr.201004515 https://doi.org/10.15826/chimtech.2023.10.1.11 https://www.sciencedirect.com/science/article/abs/pii/S0040609020306520 https://www.sciencedirect.com/science/article/abs/pii/S0921510719302429 https://www.sciencedirect.com/science/article/abs/pii/S0749603619306159 https://www.sciencedirect.com/science/article/pii/S2211379719308332 https://www.sciencedirect.com/science/article/abs/pii/S0030402618300123 https://www.sciencedirect.com/science/article/abs/pii/S003811011730014X https://www.sciencedirect.com/science/article/abs/pii/S0167931705003187 https://www.sciencedirect.com/science/article/abs/pii/S1369800121003462 https://www.sciencedirect.com/science/article/abs/pii/S0925838822009847 https://www.sciencedirect.com/science/article/abs/pii/S0040609016304072 https://www.sciencedirect.com/science/article/abs/pii/S0040609012011492 https://researchain.net/papers/10z99z1016w99wJz99zCERAMINTz99z2019z99z08z99z116 https://www.sciencedirect.com/science/article/abs/pii/S0169433220327161 https://www.sciencedirect.com/science/article/abs/pii/S0921510718300266 https://doi.org/10.1016/j.jcrysgro.2016.03.012 https://www.sciencedirect.com/science/article/abs/pii/S0169433219324511 https://www.sciencedirect.com/science/article/abs/pii/S0009261415003115 https://www.sciencedirect.com/science/article/abs/pii/S1359646219302921 https://www.sciencedirect.com/science/article/abs/pii/S0169433220324600 https://www.sciencedirect.com/science/article/abs/pii/S0925838819347450 https://www.sciencedirect.com/science/article/abs/pii/S0925838816300366 https://www.sciencedirect.com/science/article/abs/pii/S1359646220306618 https://onlinelibrary.wiley.com/doi/10.1002/pssb.19630030406 https://aip.scitation.org/doi/10.1063/1.1690112 https://www.sciencedirect.com/science/article/abs/pii/S0304399108001757 https://www.sciencedirect.com/science/article/abs/pii/S092150930601608X https://onlinelibrary.wiley.com/doi/abs/10.1002/pssr.201004515